With reference to FIGS. 1A to 1H, a conventional bumping process comprises the steps as followed, first, with reference to FIG. 1A, providing a substrate 10 having a surface 11, a plurality of bond pads 12 disposed on the surface 11, and a protective layer 13 formed on the surface 11, wherein the bond pads 12 are revealed by the protective layer 13; next, with reference to FIG. 1B, forming a metal layer with copper 20 on the bond pads 12 and the protective layer 13; then, with reference to FIG. 1C, forming a photoresist layer 30 on the metal layer with copper 20; afterward, with reference to FIG. 1D, patterning the photoresist layer 30 to form a plurality of openings 31; thereafter, with reference to FIG. 1E, forming a plurality of copper bumps 40 within the openings 31, and each of the copper bumps 40 comprises a first peripheral wall 41; after that, with reference to FIG. 1F, forming a connection layer 50 on the copper bumps 40; next, with reference to FIG. 1G, removing the photoresist layer 30; eventually, with reference to FIG. 1H, removing the metal layer with copper 20 which is not covered by the copper bumps 40 to form an under bump metallurgy layer 21 by using method of etching, and the under bump metallurgy layer 21 comprises a second peripheral wall 21a. However, when the process of “removing the metal layer with copper 20 which is not covered by the copper bump 40” is proceeding, the copper bumps 40 with material of copper may be etched as well thereafter leading an indentation of the first peripheral walls 41 of the copper bumps 40, and the indentation of the second peripheral walls 21a is severer than that of the first peripheral walls 41. Besides, for the reason that the first peripheral walls 41 and the second peripheral walls 21a are dented and exposed, an ionization phenomenon is easily occurred and leads a short condition.